# name : mantelhaen.test (pipe+mutate), Cochran-Mantel-Haenszel Chi-Squared Test for Count Data
# key : mantelhaen.test.mutate
# key : cmh.test.mutate
# contributor: Shuguang Sun
# --
${1:df} |>
mutate(
${2:aval} = as.factor($2),
${3:group} = as.factor($3),
${4:strata} = as.factor($4)
) |>
{mantelhaen.test(.\$$2, .\$$3, .\$$4)}